Jim,
Interesting questions...
Compared with a extensive arable field of say oil seed rape I would suggest that a solar park has some benefits;
1) No more pesticides into the environment.
2) A potential increase in wildflowers (good for pollinators).
3) More habitat for ground nesting birds (except maybe skylarks...)
This what the RSPB say... (see
http://www.rspb.org.uk/forprofessionals ... ?id=367959)
Photovoltaic (PV) arrays offer an opportunity to provide significant wildlife gains as well as benefits to the farmed environment. due to the extent of ‘unusable area’ between panels and in borders to the installation.
Wildlife habitats can be provided in these areas that will boost numbers of pollinating and predatory insects, and provide feeding and nesting opportunities for birds and small mammals.
In managing these habitats, nutrient input to the land and water courses will also be significantly reduced in comparison to arable use. This approach will therefore deliver multi-functional ecosystem services for agriculture and the wider environment and provide support for integrated pest management strategies.
To ensure the requirements of farmland birds and other wildlife are met it is vital to provide insect-rich habitat and winter seed-rich habitat. Farmland birds are targeted through these measures, as meeting the requirements for farmland birds also benefits a range of other groups including insects, arachnids and small mammals.
Key points
Insect-rich habitat (nectar flowers) should be sown and managed every first and second row
In-field habitat for small mammals and larvae of pollinating insects (fine grasses) should be sown and managed every third row
Seed-rich habitat (wild bird seed mixture) should be sown around the installation where access dictates and should be managed on an annual basis. This provides vital food for farmland birds and small mammals
Benefits to wildlife
Pollinating insects such as bees, hoverflies and butterflies will benefit from the 'unusable areas' planted with nectar-rich flowers
Predatory insects such as dragonflies and insect-eating birds will benefit from the increased numbers of insects feeding on the sown flowers
Seed-rich planting around the solar arrays provieds food for farmland birds and small mammals such as fieldmice.
Implementation
In-field management
To provide nesting habitat (that will also be suitable for small mammals and insects), a mixture of fine grasses should include:
Common bent
Creeping red fescue
Hard fescue
Smooth-stalked meadow grass
In order to maximise provision of pollen and nectar (both amount of the resource and period it will be available continually from spring to autumn) for a range of insects, a sown mixture of nectar flower producing plants should include:
20 per cent red clover
20 per cent white clover
15 per cent birdsfoot trefoil
15 per cent black medick
10 per cent aslike clover
10 per cent common vetch
10 per cent Phacelia
20 per cent red clover
Sow at 6 kg per acre
Or:
35 per cent sainfoin
20 per cent common vetch
10 per cent lucerne
15 per cent birdsfoot trefoil
10 per cent phacelia
5 per cent sweet clover
5 per cent red clover
Sow at 8 kg per acre
Wild bird seed mixture should be managed annually to provide seed food over the winter months.
This should include the following mix:
5 per cent mustard
25 per cent spring wheat
20 per cent white/red millet
20 per cent triticale
30 per cent barley
Sow at 50 kg per ha
Where turtle doves are present, or potential to support breeding pairs exists (eg. based on recent records), at least one margin should be planted with a mix aimed at providing a food source from April to the end of August. The following mix is suitable and should be used at 6 kg per acre:
25 per cent early English vetch
20 per cent birdsfoot trefoil
20 per cent early white clover
20 per cent black medick
10 per cent early red clover
5 per cent common fumitory
Management
Post-construction, access to the arrays is required less than once a year. Habitats can therefore be left undisturbed, with the exception of necessary habitat management (i.e. topping or re-establishment), as follows:
Sow and top fine grass areas on rotation (i.e. 1 in 2 years)
Top or graze nectar flower areas annually in September to retain flowering species. Review and re-establish as necessary every 4 – 5 years
To maintain seed production in wild bird seed mixture areas, re-sow annually. When the mixture is being re-established, removal of the plant cover and cultivation must not take place before 15th March
Turtle dove margins (where applicable) should be topped from the second year after establishment in late September-October. To maintain their suitability for foraging turtle doves, a mid-summer (i.e. mid-June to end of the first week in July) cut should be undertaken in strips of c. 3-6 m wide, distributed across the plot area.
Hedges should be managed to ensure that the production of both berry and blossom for wildlife is made available. The hedge base should be protected and enhanced for nesting birds, insects and small mammals. Where turtle doves are present, hedges should be maintained at a minimum of 4m tall to provide suitable nesting habitat.
Cutting hedges on a rotation and no more than once in every three years will ensure optimal berry and blossom production and filling any gaps to restore the hedge line would be beneficial for both landscape and wildlife. Trimming should ideally be carried out in January or February. It is essential that trimming is not carried out during the nesting season (March–September).